https://digitalcommons.calpoly.edu/nres_rpt/49
Date of Award
12-2023
Degree Name
MS in Environmental Sciences and Management
College
College of Agriculture, Food, and Environmental Sciences
Advisor
Stewart Wilson
Advisor 2
Yamina Pressler
Advisor Department
Natural Resources Management
Advisor College
College of Agriculture, Food, and Environmental Sciences
Abstract
Wildfires have been steadily increasing in both size and severity in recent decades. This global trend is most evident in California, especially the North Coast and Sierra Nevada. Although these trends are rising, there is little known about the effects of these wildfires on forest soils. Soil is the 2nd largest C sink on the planet, and the largest terrestrial bank. Without understanding the implication of rising wildfire severities on these soils, we cannot understand how to help protect this resource in the future. Due to the rapid increase in wildfire size and intensity, there is little known about the effects these “megafires” have on overall soil health, and even less known about these effects in the California Sierra Nevada region. This study aimed to understand both how field SBS and soil forming factors, represented through environmental covariates, effects soil health. 117 samples at a depth of 0-5cm were collected, then processed for sampling. Twelve soil health indicators (Total C, POXC, MinC, C/N ratio, pH, Total N, NO3N, K, P, CEC, Ca, and Mg) were selected and samples were tested in lab for each indicator. Field-validated SBS levels were assigned to each sample, and through ANOVA testing in R, where four variables were significant with SBS (Total C, C/N Ratio, NO3N, and K). Linear regression modeling was then used to observe the effects of environmental covariates on the samples. Environmental covariates were chosen to represent various soil forming factors including terrain, climate, and organisms. Each of the twelve soil health indicators were significant with at least one, if not more, environmental covariates. This information is critical in that soils are the result of not one, but several soil forming factors and processes.